ECE2017 Eposter Presentations: Thyroid Thyroid (non-cancer) (260 abstracts)
1Holycross Cancer Centre, Kielce, Poland; 2Jan Kochanowski University, Kielce, Poland; 3Medical University of Silesia, Katowice, Poland.
Background: A dynamic risk stratification with modified initial estimated risk based on response to therapy and disease course is one of the crucial changes adopted recently by the American Thyroid Association (ATA). The analysis of BRAF status is not routinely recommended by ATA, although this finding may be advantageous to individualized risk-adapted approach in papillary thyroid cancer (PTC). The methods used to detect the BRAF V600E are known of variation in the sensitivities, variable susceptibilities for DNA degradation, and possible equivocal results with direct DNA Sanger sequencing (Seq), particularly. The aim of this study was to examine the relation between the BRAF status of PTC detected applying three methods and ATA response-to-therapy categories (excellent, indeterminate, biochemical/structural incomplete), and recurrence identified after no evidence of disease (NED) or persistence disease.
Methods: Unselected 723 PTC cases with known BRAF status diagnosed 20002013, actively monitored at single institution, and reviewed retrospectively up to December 31, 2015. Genotyping of BRAF was implemented using the algorithm: Seq, followed by more sensitive allele-specific polymerase chain reaction (PCR), and real-time PCR (quantitative PCR; qPCR). Considering various limitations of particular methods 639 specimens were available for the analysis by Seq, 638 by ASA-PCR, and 705 by qPCR.
Results: BRAF V600E was found in 51.6%, 67.7%, and 67% PTCs detected by Seq, PCR, and qPCR, respectively. The indeterminate response was significantly more frequent in BRAF-positive PTCs identified by SDefault (P=0.03), but not by ASA-PCR (P=0.07), and qPCR (P=0.06). There was no significant relation between BRAF-positive cases and other not-excellent response-to-therapy categories, recurrences and persistent disease regardless of the method used.
Conclusions: The BRAF V600E mutation identified by high sensitive methods (ASA-PCR, qPCR) did not significantly alter a response-to-therapy category and out-come of PTC. However, an indeterminate response was more frequent in BRAF-mutated PTC detected by direct sequencing.